Method for Repairing or Manufacturing a Component

ABSTRACT

The invention relates to a method for repairing a structural component, especially a stator-side structural component of a gas turbine such as a housing or a guide vane ring, whereby a damaged section is separated-out from the structural component, and whereby a new section that replaces the damaged as well as separated-out section is fixedly or rigidly connected with the structural component by welding. According to the invention, the damaged section is separated-out from the structural component to be repaired in such a manner so that the length of a separating seam and therewith a later weld seam is minimized, whereby depending on the material thickness distribution along the separating seam, for providing a most uniform possible material thickness along the later weld seam, material is removed from the structural component, and whereby after the connecting of the structural component with the new section, at least the removed material is renewed by laser powder deposit welding.

The invention relates to a method for repairing a structural component,especially a stator-side structural component of a gas turbine,according to a preamble of the patent claim 1. Furthermore the inventionrelates to a method for the production of a structural componentaccording to the preamble of the patent claim 8.

In the repairing of structural components, especially of stator-sidestructural components of a gas turbine, it can be necessary to separateor remove damaged sections out of a structural component that is to berepaired, and to replace such damaged sections with a new section. Instructural components that comprise considerable material thicknessfluctuations, as is the case for guide vane rings of a gas turbine forexample, the repair proceeds in that the damaged section that is to berenewed is separated out of the structural component in such a manner sothat the most uniform possible material thickness exists along theseparating seam and thus along the later weld seam. Thereby it is to beensured that the welding can be carried out as uniform as possible andoptimally along the entire weld seam. This process, which is known fromthe state of the art, however, has the disadvantage, that very long andcomplex separating seams and therewith later weld seams can arisedepending on the section that is to be separated out of the structuralcomponent to be repaired and the material thickness distribution of thestructural component. Moreover, due to such complex as well as long weldseams, extensive preparation steps as well as post-machining orpost-processing steps can be necessary on the structural component to berepaired. This is overall disadvantageous. Since similarly in theproduction of a new part, different sections of a structural componenttypically must be connected with one another by welding, thereforesimilar problems arise in the new production or fabrication ofstructural components.

Beginning from this, it is the underlying problem of the presentinvention to provide a novel method for repairing or producing astructural component, especially a stator-side structural component of agas turbine.

The inventive method for repairing a structural component is defined inthe independent patent claim 1.

According to the invention, the damaged section is separated out fromthe structural component to be repaired in such a manner so that thelength of a separating seam and therewith a later weld seam isminimized, whereby material is removed from the structural componentdepending on the material thickness distribution along the separatingseam for providing a most uniform possible material thickness along thelater weld seam, and whereby, after the connecting of the structuralcomponent with the new section, at least the removed material is renewedby laser powder deposit welding.

In the sense of the present invention, it is proposed, to carry out theseparating seam and therewith the later weld seam with the smallestlength, and particularly substantially independently of the materialthickness distribution of the structural component to be repaired. Inorder to nonetheless provide the most uniform possible materialthickness along the weld seam during the later welding-on of a newsection replacing the separated-out section, material is removed fromthe structural component to be repaired in the area of the separatingseam, whereby at least this removed material is renewed by laser powderdeposit welding after the connection of the structural component withthe new section. This has the advantage that complex geometries ofseparating seams and weld seams can be avoided. Accordingly, astructural component to be repaired does not need to be separated intomany individual parts. Hereby, among others, cost advantages arise.

According to an advantageous further development of the invention, inorder to provide an optimal weld seam material thickness along the laterweld seam, depending on the material thickness distribution along theseparating seam, material is removed from the structural component inareas of the structural component in which the material thickness islarger than the optimal weld seam material thickness, whereas materialis applied onto the structural component in areas of the structuralcomponent in which the material thickness is smaller than the optimalweld seam material thickness.

The inventive method for producing a structural component is defined inthe independent patent claim 8.

Preferred further developments of the invention arise from the dependentclaims and the following description. An example embodiment of theinvention is explained more closely in connection with the drawing,without being limited thereto. Therein:

FIG. 1 shows a cutaway partial top plan view onto a stator-sidestructural component of a gas turbine, namely onto a guide vane ring,that is to be repaired;

FIG. 2 shows a cutaway partial side view onto the stator-side structuralcomponent of FIG. 1 that is to be repaired;

FIG. 3 shows a cutaway partial top plan view onto the stator-sidestructural component of FIG. 1 that is to be repaired, for clearlyrepresenting the inventive method; and

FIG. 4 shows a cutaway partial side view onto the stator-side structuralcomponent of FIG. 3 that is to be repaired.

In the following, the present invention is described in greater detailwith reference to FIGS. 1 to 4.

FIGS. 1 and 2 show a cutout portion of a stator-side guide vane ring 10of a gas turbine, whereby the guide vane ring 10 comprises plural guidevanes 11 that extend in the radial direction and are spaced apart fromone another in the circumferential direction. As can be seen in FIGS. 1and 2, the guide vane ring 10, in the area of a radially outwardly lyingsection 12, has a projection or protrusion 13 that protrudes outwardlybeyond the section 12, whereby the protrusion 13 represents a materialthickening. Already from this it follows that the guide vane ring 10 hasa non-uniform material thickness distribution in the area of the section12, namely has sections with a relatively small material thickness andhas the protrusion 13 with a relatively large material thickness.

In the following it is assumed as a starting point that one of the guidevanes 11 shall be exchanged for the repair of the guide vane ring 10shown in FIGS. 1 and 2. Now for example, if the guide vane 11 shown inFIG. 2 is to be exchanged, then it is directly apparent, that theshortest separating seam for separating-out the guide vane 11 out of theguide vane ring 10 would extend through the area of the protrusion 13.Since, however, the separating seam forms the later weld seam, andmoreover non-uniform material thicknesses in the area of the weld seamare disadvantageous, a separating seam that passes around the area ofthe protrusion 13 would be selected according to the state of the art.Thereby, among other things, there arises a complexly formed separatingseam as well as later weld seam.

In the sense of the present invention, it is proposed that the guidevane 11, which is to be replaced, shall be separated out of the guidevane ring 10, which is to be repaired, in such a manner so that ashortest possible separating seam and thus later weld seam arises.

Such a minimal separating seam or weld seam is identified with thereference number 14 in FIG. 3. It can be seen in FIG. 3 that thisseparating seam 14 and therewith the later weld seam extends through thearea of the protrusion 13. In order to nonetheless provide a mostuniform possible material thickness over the area of the later weld seamindependently of the material thickness distribution of the originalstructural component, material is removed in the sense of the presentinvention along the separating seam and therewith the later weld seam.In the example embodiment of FIG. 3, the protrusion 13 is removed. Thisis shown by FIG. 4, which shows the section 12 without the protrusion13. Moreover FIG. 4 shows a guide vane 15, which replaces the guide vane11 that is to be separated-out. The guide vane 15 has a materialthickness matched or adapted to the section 12 in the area of the weldseam 14. Hereby it is ensured that a weld seam with optimalcharacteristics can be provided, without the necessity of complexlyguided separating seams or weld seams.

It thus lies in the present invention, to remove material in areas ofthe structural component that are characterized by a material thickeningin the area of the separating seam, depending on the material thicknessdistribution along the shortest selected separating seam, for providingan optimal weld seam material thickness along the later weld seam. Insuch areas of the separating seam, in which the material thickness isthus greater than an optimal weld seam material thickness, material isremoved from the structural component. It can, however, also be thecase, that the structural component to be repaired comprises, in asection of the separating seam, a material thickness that is smallerthan the optimal weld seam material thickness. In this case it ispossible to apply material onto the structural component in the area ofthe separating seam and therewith later weld seam by laser powderdeposit welding.

As can be seen especially from FIG. 3, when separating-out the guidevane 11 out of the guide vane ring 10, the separating seam 14 wouldextend into the area of a lateral bounding contour 16 of the section 12,and would thus end “in free open space”. A separating seam as well as alater weld seam, which is not enclosed on all sides by material, butrather ends “in free open space” can lead to considerable deformationsof the structural component. Therefore, in the sense of the presentinvention, a material thickening 17 is applied by laser powder depositwelding in the area of the bounding contour 16 before the separating-outof the guide vane 11 out of the guide vane ring 10, in order to ensurethat the separating seam 14 and therewith later weld seam is enclosed onall sides by material.

Also this lies in the basic idea of the invention, to ensure an optimalweld seam material thickness in the entire area of the weld seam, eitherby removing or by applying material in the area of the structuralcomponent to be repaired, namely in the area of the separating seam 14or weld seam.

At this point it is mentioned that the removal of material as well asthe application of material, if applicable, for providing the mostuniform possible material thickness along the later weld seam 14 can becarried out either before the separating-out of the guide vane 11 to bereplaced or after the separating-out thereof. If material must beapplied in order to avoid separating seams ending “in free open space”,then this takes place before the separating-out of the structuralcomponent section to be replaced. If, to the contrary, material must beremoved, then this takes place after the separating-out of thestructural component, since in this manner removal work in the area ofthe structural component section to be replaced can be avoided.

After the connecting of the new guide vane 15 (see FIG. 4) with theguide vane ring 10 by welding, the material that was removed to providethe uniform material thickness along the weld seam 14 is renewed bylaser powder deposit welding. In the illustrated example embodiment thismeans that the protrusion 13, which was removed for providing theoptimal weld seam material thickness, is renewed by laser powder depositwelding after the welding of the guide vane 15 with the guide vane ring10.

If, to the contrary, material was applied for providing the optimal weldseam material thickness, then, in the sense of the present invention,this is removed after the welding. In the illustrated example embodimentthis would mean that after the connecting of the guide vane 15 with theguide vane ring 10, the material thickening 17 is again removed, so thatthe continuous bounding contour 16 is reproduced.

Following the application or removal of material, a surface machining orprocessing can be carried out, in order to ensure flow-technicallydefined component contours of the repaired structural component, namelyof the repaired guide vane ring.

Accordingly, with the inventive method, complex geometries of separatingseams as well as weld seams are avoided in the repair of structuralcomponents.

This similarly pertains for the new production of a structuralcomponent. Local protrusions or material thickenings can be produced bylaser powder deposit welding subsequently after the connecting. Arisingherefrom are significant cost advantages, as well as logistic advantagesand qualitative advantages, because on the one hand simple weld seamsand on the other hand weld seams with a uniform material thickness areprovided.

1. Method for repairing a structural component, especially a stator-sidestructural component of a gas turbine such as a housing or a guide vanering, whereby a damaged section is separated out from the structuralcomponent, and whereby a new section that replaces the damaged as wellas separated-out section is securely or rigidly connected with thestructural component by welding, characterized in that the damagedsection is separated-out from the structural component to be repaired insuch a manner so that the length of a separating seam and therewith alater weld seam is minimized, in that material is removed from thestructural component depending on the material thickness distributionalong the separating seam for providing a most uniform possible materialthickness along the later weld seam, and in that at least the removedmaterial is renewed by laser powder deposit welding after the connectingof the structural component with the new section.
 2. Method according toclaim 1, characterized in that, depending on the material thicknessdistribution along the separating seam, for providing an optimal weldseam material thickness along the later weld seam, material is removedfrom the structural component in areas of the structural component inwhich the material thickness is larger than the optimal weld seammaterial thickness, whereas material is applied onto the structuralcomponent in areas of the structural component in which the materialthickness is smaller than the optimal weld seam material thickness. 3-7.(canceled)
 8. Method for producing a structural component, especially astator-side structural component of a gas turbine, such as a housing ora guide vane ring, whereby at least two sections are connected securelyor rigidly with one another by welding, characterized in that thesections to be connected with one another, in the area of the later weldseam, comprise a uniform material thickness along the weld seam, wherebyafter the connecting of the sections, material is applied by laserpowder deposit welding for providing defined structural componentcontours
 9. Method according to claim 1, characterized in that theremoving of material for providing the most uniform possible materialthickness along the later weld seam is carried out either before theseparating-out or after the separating-out of the damaged section. 10.Method according to claim 2, characterized in that the removing ofmaterial as well as the applying of material for providing the mostuniform possible material thickness along the later weld seam is carriedout either before the separating-out or after the separating-out of thedamaged section.
 11. Method according to claim 1, characterized in thatthe damaged section is separated-out of the structural component to berepaired, with a shortest possible length of a separating seam andtherewith a later weld seam.
 12. Method according to claim 1,characterized in that, after the connecting of the structural componentwith the new section, on the one hand in the area of the structuralcomponent, the material removed from the structural component, as wellas on the other hand in the area of the new section, material forproviding defined structural component contours of the repairedstructural component, are applied by laser powder deposit welding. 13.Method according to claim 12, characterized in that thereafter a surfacemachining is carried out.
 14. Use of a method according to claim 1 forrepairing stator-side structural components of a gas turbine, especiallyan aircraft engine, such as a housing or a guide vane ring.